Scientist find hints of the Higgs, but no smoking gun yet

No scientists haven’t found the Higgs boson, popularly known as the “God particle.” At least not yet.

Instead, in a wonderful display of science-in-progress, physicists in Europe have announced preliminary results that hint at the existence of the Higgs. After two years of collecting data at the massive particle accelerator in Switzerland, the Large Hadron Collider, scientists say they have found “intriguing” signs of the particles.

“Over the last few weeks we have started to see an intriguing excess of events in the mass range around 125 GeV,” said ATLAS experiment spokesperson Fabiola Gianotti.”This excess may be due to a fluctuation, but it could also be something more interesting. We cannot conclude anything at this stage. We need more study and more data.”

But that doesn’t mean they’ve found the Higgs, the existence of which would confirm theories of how all particles in the universe get mass. For scientists it would be a huge deal.

There are two different “experiments” at the Switzerland collider collecting and examing data from the particle acclerator. One is called CMS, the other ATLAS.

The CMS detector at the Large Hadron Collider. (CERN)

Essentially, physicists are smashing together particles at very high velocities, and in these tiny but very energetic collisions they hope to create enough energy to bring the Higgs boson into life.

But the particle exists only for a very small fraction of a second, so scientists cannot observe it directly. Instead with their “particle detectors” they look for evidence of its existence in the patterns of particles left behind.

In sorting through unimaginable amounts of data scientists on one of the experiment teams, CMS, say they they have observed a particle that could be the Higgs with a 1.9 sigma degree of confidence. This means there is about a 5 percent chance of it being a statistical fluke. On the other experiment, ATLAS, confidence is a little bit higher still.

In particle physics that’s not good enough. (About five sigma would give scientists full confidence in a new discovery). More data is therefore needed, and a final answer on whether this particle is actually the Higgs will probably not come for another year.

I’ll have more technical information in a minute, but first here’s some comments on today’s announcement from Rice University physicist Paul Padley, who is a member of the CMS research team.

“It can not be over stated how spectacularly well the detectors and accelerator are working,” he said. “This is an incredibly difficult thing to do and yet the accelerator is working well beyond expectations and the detectors have done an incredible job of capturing the data. Analyzing the data has requirement people working around the world using computing farms spread out in a tremendous network – the grid. Every aspect of this challenge is hard, the detectors, the electronics, the computing. Regardless of the final outcome of the experiment, society has already benefited by the technology leaps that are necessary to make this experiment work. ”

Who cares about the Higgs?

If found it would confirm the models scientists have for why particles in the universe actually have mass. Once scientists have a chance to study and understand its properties, it may also help physicists link gravity to the other major forces: strong nuclear, weak nuclear and the electromagnetic force.

And who cares about that?

Fully understanding the quantum nature of the universe could very well open a new era of technological discovery.

If they discover these quantum properties, you could see an whole new era of technological advancements. A fundamental understanding of microbes led to antibiotics. It is impossible to say what technology knowing the Higgs would unlock, but that doesn’t discount its significance.

MORE TECHNICAL STUFF

For those still reading, here’s some more detail on today’s announcements.

Physicist measure the mass of particles in electron volts, which is possible as mass and energy are often interchanged. The proton, for example, “weighs” just under 1 GeV/c2. (That is 1 billion electron volts/speed of light squared).

How big is the Higgs?

The Large Electron-Positron Collider, a predecessor to the Large Hadron Collider in Europe, had previously ruled out the Higgs Boson having a mass less than 114.4 GeV/c2.

The CMS experiment at the Large Hadron Collider has all but ruled out the existence of the Higgs between 127 and 600 GeV/c2.

Therefore scientists have strongly believed they would find a very large particle with a mass somewhere between 115 and 127 GeV/c2.

That’s what’s so exciting about today’s announcement. The physicists have found an “intriguing excess” of events in this very area, strongly indicative of the Higgs. Here’s a graphic from the CMS experiment that shows this.

Click to enlarge. (CMS experiment)

What does it show?

Padley explains: The black line shows our limit on the production of the Higgs boson. The dashed line shows our expected limit. If the black line is above the dashed line, then we have more events than expected in the case where there is no Higgs boson. If the black line is below the red line, then the data is incompatible with the Higgs boson hypothesis. With this result there is a very small window left for the Higgs boson to hide (115 to 127 GeV/c2) the region where the black line is above the red line. Intriguingly in that window there is an excess of events. The statistical significance of the excess in the CMS data is approximately equivalent to tossing a coin and getting 4 heads in a row. We will need more data to understand if that excess is a consequence of the Higgs boson or if it was just a statistical fluke.